The demand for increased security of telecommunications systems continues to grow as increased levels of confidential information is passed along wired and wireless networks. As more users increasingly are outside their normal place of business, for example, on travel or telecommuting, the demand for devices that render unintelligible unauthorized interception of voice, data, facsimile and other electronically transmitted information also increases. If, for example, a telecommuting user contacts a second user using a conventional telephone system and expects to discuss sensitive information, the telecommuting user may wish to encrypt the conversation or any data transmitted to frustrate unauthorized interception of their conversation. As many users possess wire-based telephones, facsimile machines, computers, and wireless communication devices, such as cellular telephones, it is desirable to provide a portable security device capable of performing encryption/decryption functions in connection with these existing devices and other types of communication equipment.
However, the ability of a single device to handle existing and intended communication equipment many telephone systems have significant limitations on the transmission bandwidth. In digital terms this relates to a limitation of speed or baud rate that digital data may be transmitted. Hence, digital transmission over limited bandwidth telephone lines of conventional high-speed digital voice data creates a noticeable alteration in the received and reconstructed voice data. Furthermore, encryption processing creates a still more noticeable alteration in the received and reconstructed voice data as the encryption process adds a significant number of encoding bits that do not contribute to the audio information.
Accordingly, there is a need for a portable device for encryption/decryption information from one or more communication sources that provides increased security of the transmitted message while allowing for transmission of acceptable voice data over networks of different available bandwidths.
FIGS. 1 through 6 and the accompanying detailed description contained herein are to be used as an illustrative embodiment of the present invention and should not be construed as the only manner of practicing the invention. It is to be understood that these drawings are for purposes of illustrating the concepts of the invention and are not to scale. It will be appreciated that the same reference numerals, possibly supplemented with reference characters where appropriate, have been used throughout to identify corresponding parts.